msem-instigator

Flying
Assault {2}{B} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)
When Harbinger of Locusts assaults, you may search your library for an Insect card, reveal it, put it into your hand, then shuffle.

When Hardlight Visionary enters, create a Function token with “Until end of turn, target creature becomes a 5/5 Dragon and gains flying.” (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)

Reach
Whenever one or more creatures with flying attack, harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — Harpstring Ranger gets +2/+2 until end of turn. Untap it.

Flying
Harrier's Falcon can't attack or block alone.

When Haunted Hermit enters, choose one —
• Put a +1/+1 counter on Haunted Hermit.
• Create a 1/1 white Spirit creature token with flying.

Flying
Whenever Haunter of the Deadlands attacks, Spirit creatures you control get +1/+1 until end of turn.

Flying
Whenever Haunting Horseman deals combat damage to a player, that player discards a card.

Flying, lifelink

Hazy Coppice enters tapped.
{T}: Add {U} or {B}.
{2}{U}{B}: Until end of turn, Hazy Coppice becomes a 4/4 blue and black Bird creature with with flying and “Whenever this creature attacks or blocks, torment yourself.” It's still a land. (To torment yourself, lose 3 life unless you discard a card or sacrifice a nonland permanent.)

Flying
Cadence (Whenever you cast a spell, if its mana value is greater than this creature's power, put a +1/+1 counter on this creature.)

Flying, vigilance, deathtouch, lifelink

Flying
When Heartless Host enters, arm target creature. (Create a colorless Equipment artifact token with “Equipped creature gets +1/+0” and equip {2}, then attach it to that creature.)

Kicker {2}{B} (You may pay an additional {2}{B} as you cast this spell.)
Flying
When Heartstabber Mosquito enters, if it was kicked, destroy target creature.

Flying
When Heaven's End Chronicler enters, mill three cards, then choose three cards in your graveyard. An opponent separates them into two piles. Return one pile to your hand.

Flying
When Heaven's Eyes enters, create a 1/1 white Bird creature token with flying. Then you gain 1 life for each creature in Heaven's Eyes's pack. (Two or more creatures you control with equal power are in a pack.)

Flying
{T}, Tap another untapped creature in Heaven's Gale Harrier's pack: Tap target creature. (Two or more creatures you control with equal power are in a pack.)

Flying
If a source without flying would deal damage to you, prevent 2 of that damage.
Crew 5

Flying, lifelink

Create a 2/2 white Angel creature token with flying.
Acquiesce (If you cast this spell from your hand, exile it as it resolves. When one or more creatures you control deal combat damage to an opponent, you may cast this card from exile without paying its mana cost.)

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever a creature you control with flying attacks, it gets +1/+1 until end of turn.

{T}: Add {C}.
When Heavenly Temple enters, target creature gains flying until end of turn.
{2}: Return Heavenly Temple from the battlefield to its owner's hand.

Enchant creature
Enchanted creature has flying and can only block creatures with flying.

At the beginning of your upkeep, you gain 1 life. Then each opponent may give themselves a poison counter. For each opponent who doesn't, create a 2/2 white Angel creature token with flying.

Flying (This creature can't be blocked except by creatures with flying or reach.)
Heavensent Emissary enters with a +1/+1 counter on it for each other creature with flying you control.

Flying
When Helar Ritualist enters or whenever you cast a spell, if {W}{B} was spent to cast it, each opponent loses 3 life and you gain 3 life. Put a +1/+1 counter on Helar Ritualist.